Inboard-outboard drive mechanism for boats

ABSTRACT

An all gear drive mechanism for boats comprising a train of gears loosely mounted on a horizontal idler shaft mounted at opposite ends in a stationary housing for transmitting power from one or each of two engines to a vertical drive shaft operatively connected to propellers mounted in a lower housing rotatable relatively to the stationary housing by steering mechanism controlled by a steering wheel. The idler shaft has an opening extending transversely therethrough, surrounded by an extrusion in the form of a collar perpendicular to the axis of the idler shaft, and the vertical drive shaft extends through said opening and collar and is supported by the idler shaft.

[ Nov. 6, 1973 lNBOARD-OUTBOARD DRIVE MECHANISM FOR BOATS [76] Inventor: Lyle C. Pinkerton, Henderson, C010.

221 Filed:' May 3,1971" [21] Appl. No.: 139,562

[52] 11.8. C1. ...115/35, 115/37, 115/41 R, 115/34 C [51] Int. Cl..... B63h l/l 4, B63h 51/10, B63h 25/42 [58] Field of Search ll5/4;1 R, 41 HT, 115/34, 35, 37, 38, 34 C [56] References Cited UNITED STATES PATENTS 3,486,478 12/1969 Halliday 115/35 1,781,656 ll/l930 Day 115/37 1,616,415 2/1927 Day 115/37 3,122,123 2/1964 Shallbetter et al 115/41 R 2,672,115 3/1954 Conover 115/37 X 6/1964 McCormick 115/41 R 3,087,553 4/1963 Kostyun ..115 340 Primary ExaminerRobert S. Ward, Jr. Attorney-Bertha L. MacGregor v 57 ABSTRACT An all gear drive mechanism for boats comprising a train of gears loosely mounted on a horizontal idler shaft mounted at opposite ends in a stationary housing for transmitting power from one or each of two engines to a vertical drive shaft operatively connected to propellers mounted in a lower housing rotatable relatively to the stationary housing by steering mechanism controlled by a steering wheel. The idler shaft has an opening extending transversely therethrough, surrounded by an extrusion in the form of a collar perpendicular to the axis of the idler shaft, and the vertical drive shaft extends through said opening and collar and is supported by the idler shaft.

20 Claims, 9 Drawing Figures PAIENTEDNBV 61915 sum 1W5 INVENTOR. LYLE C. PINKERTON BY ATTORNEY Pmmmuv ems sumaurs ATTOIIYNEY PAIENTEDNBV 81973 IN VEN TOR. LYLE C. P/NKERTON BY ATTORNEY PAIENIEmwv ems SHEET. W W 5 R m m. V N I LYLE C. PINKERTON ATTORNEY PAIENIEDNBV 61913 3.769.930

sum 5 or 5 INVENTOR.

LYLE C. P/NKERTON MW r.

' ATTOHN E Y r 1 INBOARD-OUTBOARD' DRIVE MECHANISM FOR BOATS This invention relates to inboard-outboard drive mechanism for boats. I The main object of this invention is to provide an all gear drive mechanism to transmit power from one or more engines to a centrally located propulsion drive means, with the capability of 360 steering and 180 lifting of the lower propulsion unit. 7

Another object of the invention is to utilize the power of two internal combustion engines and to transmit the combined power of the engines to propellers which are part of a single propulsion unit. 7

Another object of the invention is to utilize the combined power of two engines transmitted through an all gear drive train to a single propulsion unit, whereby the propulsion unit may be mounted in the transverse center of the boat. This construction eliminates side draft while operating with one motor, as contrasted to the side draft encountered when using a conventional twin engine installation where two propulsion units are required. Thus side draft is avoided and steering made easy when my construction is employed, regardless of whether one or both engines are operating.

An advantage resulting from the transverse center location of the propulsion unit, inline with the keel, is the elimination of the tendency of the propeller to cavitate in a high speed banking turn, such as would be experienced by the upper unit of a two propulsion unit installation. I

Another object of the invention is to provide means for housing the mechanism in an oil bath which can be checked, drained and replenished from inboard the boat.

whereby stress on the steering control cables is reduced to a degree corresponding to the reduction in steering gears. The described mechanism permits the use of rotatable steering means instead of reciprocating mecha nism, making it possible to install automatic steering, such as automatic pilots, economically. The steering mechanism provides for 360 steering without stress on the gear train.

Another advantage of the invention is the ease and simplicity of steering a boat equipped with one propulsion unit powered by two engines as compared with two propulsion units powered by two engines.

ln addition to the aforementioned advantages of utilizing twin engines for power transmission to a single propulsion unit is the safety factor of having an available engine in the event of malfunction of the other. This advantage is especially pertinent in connection with large boat equipment, where substantial horsepower is required for efficient operation, and diesel engines.are chosen because they are explosion proof.

A further advantage resulting from my two-engine, single-propulsion unit combination is that while having the security of twin-engine installation, only the weight and drag of one propulsion unit exists, and by eliminating the prior art use of twin propulsion units, I avoid the need for individual transmissions, dual steering hookups, dual shifting hook-ups, etc.

The advantages resulting from this twin-engine single propulsion unit combination aforementioned include those related to horsepower and weight factors. I have found that twin engines having combined horsepower substantially equal to that of a single engine, marketed by the same manufacturer, weigh substantially less than the single engine. The following specifications published by three major Diesel manufacturers show that pairs of twin engines weigh substantially less than single engines of the same manufacture and comparable horsepower:

Caterpillar Tractor Company Model Horsepower Weight D343Ta 460 5775 3160 2 2l0=420 2X l735=3470 Cummins Engine Co.

Vl2-700-M 700 7993 VT8-370-M 2 X 370 740 2 X 2775 5550 Detroit Diesel Engine Division lZV-l49 800 12500 8V7lT 2 X 380 760 2 X 3250 6500 The foregoing weight-horsepower comparisions prove the advantage of this invention in utilizing twin engines to obtain the horsepower needed to propel craft speedily without excessive weight that makes it impossible to plane the craft. Adding to this advantage of relatively high horsepower coupled with relatively low weight, is the limiting of the weight of the drive means by use of a single propulsion unit in place of the conventional twin propulsion units.

One of the objects of this invention is to provide a horizontally disposed idler shaft, mounted at opposite ends in fixed housings, on which the propulsion unit drive gearing and lifting gearing are mounted, whereby the pivotally mounted gear housing and parts carried thereby can be actuated for raising and lowering the propulsion unit without physical strain on the pivotal gear housing. Apart from the specific lifting mechanism and its advantages with respect to the raising and lowering of the propulsion unit, which will be the subject of a separate application, the provision of the horizontal idler shaft and the gearing associated therewith results in an exceptionally compact and efficient power transmission mechanism in which U-joints and rubber boots and the like used for steering and lifting of the propulsion unit are eliminated.

My invention also includes novel means for reversing the direction of thrust of the propulsion unit which will be the subject of a separate patent application, said reversing means avoiding the interruption and reversal of the drive gear train disclosed herein.

In the drawings:

FIG. 1 is an elevational view of the stern portion of a boat on which is mounted the inboard-outboard propulsion mechanism embodying my invention.

FIG. 2 is a top view of the same.

FIG. 3 is an elevational vertical rear view, partly in section, with the outer housing partially omitted, of the central section and adjacent portions of each of the two side sections of the propulsion mechanism, showing the lower propulsion unit including housing, propellers and their drive mechanism turned ninety degrees from their straight forward drive positions.

FIG. 4 is a view similar to FIG. 3, on an enlarged scale, of the upper central section and lesser portions of adjacent side sections, with the lower propulsion unit omitted, showing in section some of the parts shown in elevation in FIG. 3.

FIG. 5 is a top plan view, with the top of the outer housing omitted, on the same scale as FIG. 4, showing the propulsion mechanism with the engine driven drive shafts broken away.

FIG. 6 is a horizontal sectional view of a detail of construction in the plane of the line 6-6 of FIG. 4.

FIG. 7 is a vertical section in the plane of the line 7-7 of FIG. 2, showing the upper portion of the propulsion mechanism.

FIG. 8 is an elevational view, partly in section, of the timing mechanism associated with the reversing and steering means.

FIG. 9 is a perspective view of part of the horizontal idler shaft.

In the embodiment of the invention shown in the drawings, a boat 10 has a transom 11 on which the outboard upper part 12 of the propulsion unit is mounted, with the lower or propeller unit 13 depending therefrom. Inboard parts of the mechanism include two engines 14, 15, a motor 16, steering control wheel 17, flexible steering shaft 18, and timing mechanism housing 19 containing parts shown in FIG. 8, to be described hereinafter. Other inboard parts are the reverse control lever 20 and lead 21.

The propulsion unit 12 comprises a housing having a central section and adjacent end sections 26, 27, partly integrally formed. The central section 25 consists of a transom-contacting wall, with the top, front and bottom cutaway to permit rotation of an inner central housing. As shown in FIG. 5, the central section includes an inner housing 28 which is rotatable and concentric with the inturned flange members 29, 30, on the housing sections 26, 27, respectively. Seals 31 and roller bearings 32 are located between the flange 29 and inner housing 28, and between the flange and housing 28. This construction facilitates relative rotary movement between the inner housing 28 and the stationary housings 26, 27, for the purpose of lifting the propeller unit portion of the mechanism.

'The engine 14 is operatively connected to .drive mechanism hereinafter described by a horizontal rotatable shaft 35, and engine 15 is operatively connected to the said drive mechanism by a horizontal rotatable shaft 36. The shafts extend through the housing sections 26, 27, respectively, as shown in FIG. 5. The motor 16 is operatively connected to propeller unit lifting mechanism, to be referred to hereinafter, by a horizontal shaft 37 (FIG. 5) which extends through the housing 26 in a location adjacent the central section housing 28 where it functions to rotate and operate means for pivotally lifting the housing 28 and contents.

Referring now to the propulsion unit drive mechanism in the housing members 25, 26, 27, as shown in FIGS. 3-5, a hollow horizontal idler shaft 40 is mounted at each end in a bearing support 41 and hanger 42, the latter being fastened to the housings 26 and 27, respectively, by retaining bolts 43. The idler shaft 40 is supported by the two stationary housings, 26, 27, and carries the operative drive mechanism without any stress on the movable housing 28 and its contents. The idler shaft 40 is provided with an extrusion 44 in the form of a collar (FIG. 9) having an internal diameter larger than the external diameter of the shaft 40 for reception of an upper reverse dog gear 45, upper bearing 46 and lower bearing 47 (FIG. 4), said bearing members being located between the extrusion 44 and reverse dog gear 45. A retaining ring 48 is located between the bearing members 46, 47, and the extrusion 44 on shaft 40. The extrusion 44 forms a housing and retainer for the bearing members.

A vertical main propulsion shaft 50 extends through the reverse dog gear 45, which has splined on its upper end a power accumulating gear 51 retained by a snap ring 52. The reverse dog gear 45 is loose on the vertical shaft 50.

The power accumulating gear 51 has rotary motion transmitted to it through the following mechanism: engine shaft 35 rotates pinion 53 and simultaneously engine shaft 36 rotates pinion 54; pinion 53 meshes with and drives power transfer gear 55 loose on shaft 40 while simultanously pinion 54 drives power transfer gear 56 which is loose on shaft 40; power transfer gear 55 engages a one-way rolling clutch assembly 57 while simultaneously power transfer gear 56 engages one way rolling clutch assembly 58; rolling clutch assembly 57 when in locked position transmits rotary motion to transfer gear 59 while simultaneously rolling clutch assembly 58 when in locked position transmits rotary motion to transfer gear 60. The gear train 55-60 is loosely mounted on idler shaft 40 and sustained on the idler shaft with suitable bearings to allow the gear train to rotate freely. Gears 59 and 60 mesh with and rotate the power accumulating gear 51 which rotates the dog gear 45 loosely mounted on vertical drive shaft 50. Thrust bearings for both transfer gears 59, 60 are designated 61.

The power accumulating gear 51, splined over the upper reverse dog gear 45, retains the gear 45 and bearings 46, 47 in the extrusion 44 of the idler shaft 40. A dog clutch 65 is splined onto the vertical drive shaft 50. When the clutch 65 is in driving engagement with the power accumulating gear 51, as shown in FIG. 4, I

the vertical shaft 50 is rotated and transmits rotary motion through gear 66 fixedly mounted on the lower end of shaft 50 to the propeller drive gears 67, 68 fixedly mounted on propeller shafts 69, 70, respectively, to drive propellers 71, 72, respectively, in counter rotation.

The dog clutch 65 is moved into or out of driving engagement with the power accumulating gear 51 by the following described mechanism: A clutch control lever extends inwardly through the transom 11 and is provided with a clutch control actuating ball 76 on its outboard end. Between its ends the lever 75 is mounted in a retaining ring 77. The clutch control actuating ball 76 engages a clutch plate 78 to rotate the plate, causing the clutch actuating rollers 79 in tapered slots to be forced against a clutch actuating plate 80 to thereby push the plate 80 away from the clutch 65. This movement applies outward pressure or pulling motion on the shifting fork actuating arm 81 which is pivotally connected at 82 to an ear on the shifting fork 83. The shifting fork 83 engages the clutch 65 to lower it into engagement with the power accumulating gear 51 as shown in FIG. 4 to transmit driving motion to the vertical shaft 50. The shifting fork actuating arm 81 is provided with a roller 84 which moves in an annular slot cast in the clutch actuating plate 80.

When the shifting fork 83 is raised, the clutch 65 is moved out of engagement with gear 51 in nontransmitting position. This is its position when disenpeller unit will be described briefly. The reversing mechanism will be the subject of another application. The control lever 20, located inboard, when moved rearwardly, actuates a two-way switch (not shown) which feeds electrical current to a solenoid 85, and to a solenoid 112 to be described hereinafter as part of the timing mechanism of FIG. 8. The reverse actuating solenoid 85 actuates a mutilated gear 86 which meshes with teeth on a clutch plate 95. The gear 86 is mounted on a pin 87 suitably supported in idler shaft 40. The solenoid 85 is electrically connected to the timing mechanism of FIG. 8 by leads 88. Below the upper reverse dog gear 45 is a lower reverse dog gear 90 splined over a sleeve 91. The sleeve 91 is splined into a multiplate clutch arrangement 92, the latter being retained between the sleeve 91 and a clutch plate 93 splined into the lower unit housing 94. The lower unit housing is screwed into a steering gear referred to hereinafter as 102 and retained by a splined sleeve 103. The lower reverse dog 90 is moved into engagement with the upper reverse dog gear 45 by'means comprising the clutch plate 95 rotating on ball bearings 96 retained in tapered slots in the clutch plate 95, which apply upward pressure on the lower reverse dog gear 90 and thereby force it upwardly into. contact with the upper dog gear 45. Thus power delivered through the upper dog gear 45 rotates the lower unit housing 94. Rotationof the lower unit housing 94 is terminated by the action of the timing wheel 114 described hereinafter which trips a twoway switch 22 thus de-energizing electrical solenoids 85 and 112, allowing return spring 97 to force the lower dog gear 90 downwardly and disengaging from the upper dog gear 45. At the same time, the return spring 116 forces the timing clutch gear 113 onto the splines of the steering wheel shaft 110.

The lower unit housing 94 and parts associated therewith are rotated for two purposes: reversing and steering. For steering, power is conveyed through the steering wheel 17 and flexible shaft 18, the latter including interconncted ends and mechanism shown inFIG. 8 to be described .in detail hereinafter. Power is applied to a steering shaft and gear 100 located in the housing 27; the shaft and gear 100 rotate a transfer gear 101 rotatably mounted on a pin projecting from idler shaft 40 as shown in FIG. 4. Steering transfer gear 101 rotates the steering gear 102. Steering gear 102 is firmly fastened to the lower unit housing 94 through a threading arrangement and firmly retained by a splined collar 103. The collar 103 is preventedfrom upward movement by a spring 104. As the steering wheel 17 is rotated, the

' lower unit 94 and parts carried thereby are rotated for directional control of the boat.

As shown in FIG. 8, the flexible shaft 18 has a splined end 110 operatively connected to the shaft 111 connected to steering shaft and gear 100. At the same time that electrical current is fed-to the reverse actuating solenoid 85, current also is fed to a timing gear solenoid 112 which causes the lever 117 to move the timing clutch gear 113 to engage the timing gear 114 and thus disengage it from the splined shaft 110. As the lower unit 94 rotates, negative motion is fed from the steering gear 102 to the steering transfer gear 101 to the steering pinion gear and shaft 100 and into the flexible shaft 111 to timing clutch gear 113, causing the timing gear 114 to be rotated in an annular path. The timing gear is so designed that when the lower unit has rotated 180, the timing gear 114 has completed a 360 degree rotation. The timing gear has a protruding lip 115 which on completion of one revolution trips the two way switch 22, thus opening the electric circuit and allowing the electric solenoids and 1 12 to become deactivated, which allows the return spring 116 to force the timing clutch gear 113 onto the splines of the steering wheel'shaft to return to normal steering. At this same time, return spring 96 forces the lower reverse.

dog gear'90 downward, disengaging the dog gears 45 and 90 and stopping rotation of the lower unit 94. As shown in FIG. 8, the reversing mechanism is disengaged and the steering mechanism is operatively engaged.

Means for lifting the lower housing 94 and propellers will be described briefly. The lifting means will be the subject of another application. As shown in FIGS. 2, 3 and 5, thelifting means comprises the motor 16, motor shaft 37, worm 120, worm release spring 121, worm retaining collar 122, thrust bearing 123, worm ring gear 124. Rotation of the shaft 37 with worm 120 in mesh with ring gear 124, which is splined to the center housing 28, causes the said housing 28 to rotate relatively to stationary housings 26, 27, for raising the propeller unit 180.

Some details of construction not heretofore numerically designated include the following: suitable bearings for engine shafts 35, 36, in housings which are part of the housing sections 26, 27, bearings 131 for the motor shaft 37 in a housing which is part of the housing section 25, and drain plugs 132 in housing sections 26, 27, as shown in FIG. 5. In FIGS. 3 and 4 are shown threaded plugs 133 in the central housing 28 which are removable to facilitate insertion, one by one, of the ball bearings 32 between the central housing 28 and flanges 29 and 30, respectively, of the stationary housing sections 26, 27. Guide arms 134 extend rearwardly from the stationary housings 26, 27 for housing latching and trim mechanism described in a separate application. Various bearings and springs are shown without numerical designations, their functions being obvious.

I claim:

1. Drive mechanism for a boat comprising a. a housing for outboard mounting on the stern of a boat,

b. an idler shaft having an opening extending therethrough, said shaft extending axially transversely of the boat and mounted at its ends in said housing,

c. a vertical rotatable drive shaft extending through said opening in the idler shaft,

(1. a clutch gear on the upper end of the vertical drive shaft, said drive shaft and gear being supported by the idler shaft,

. e. an engine,

f. gearing including a train of gears loosely mounted on said idler shaft operatively connecting said engine with said clutch gear on said driveishaft for rotating said shaft, and

g. a propeller unit driven by said vertical shaft.

2. Drive mechanism defined by claim 1, in which the gearing includes a power accumulating gear rotatable about the vertical shaft by power transmitted through said engine operated gears, and means actuating the clutch gear into and out of engagement with said power accumulating gear.

3. Drive mechanism defined by claim 2, in which the means actuating the clutch gear comprises a pivotally mounted shifting fork engaging the clutch gear, an operating lever, and means pivotally connecting the lever and shifting fork for transmitting lifting and lowering movement to the fork and clutch gear.

4. Drive mechanism defined by claim 3, in which the means actuating the clutch gear includes a rotatable clutch plate, clutch actuating rollers in tapered slots, and a clutch contacting plate forced by the rollers into contact with the shifting fork.

5. Drive mechanism defined by claim 2, in which the gears loosely mounted on the idler shaft connecting the engine with the clutch gear comprise a pinion rotated by said engine, a power transfer gear driven by said pinion, a one way rolling clutch assembly engaged by said transfer gear, and a second transfer gear rotated by said clutch assembly for rotating said power accumulating gear.

6. Drive mechanism defined by claim 5, in which the one way rolling clutch assembly comprises rollers movable to motion transmitting positions between the first and second transfer gears when the engine is operating and automatically movable to non-transmitting positions when the engine is idle.

7. Drive mechanism defined by claim 1, in which the propeller unit includes a lower housing rotatable about the axis of the vertical shaft, and which includes a steering wheel controlled, power actuated gearing supported by the idler shaft and operatively connected with said lower housing to impart steering rotation to said lower housing and propeller unit.

8. Drive mechanism defined by claim 7, in which the idler shaft is hollow, and the power actuated gearing includes a shaft and pinion in the hollow idler shaft, a transfer gear, and a steering gear in mesh with the transfer gear, said steering gear being held on the lower housing by a splined collar.

9. Drive mechanism defined by claim 1, in which the idler shaft is provided with an extrusion perpendicular to the axis of the shaft surrounding said opening in the shaft, and in which the drive shaft and clutch gear thereon are supported by the extrusion of the idler shaft.

10. In combination with a boat, drive mechanism comprising i a. a main housing mounted outboard on the stern of a boat,

b. an idler shaft having an opening extending therethrough midway between the shaft ends, said shaft extending axially transversely of the boat and mounted at its ends in opposite ends of the housing,

0. a vertical drive shaft extending through the opening in the idler shaft,

d. a single lower housing and a propeller unit in the lower housing located in alignment with the keel of the boat, said lower housing being rotatably mounted on the main housing, and said vertical drive shaft extending into the lower housing and operatively connected to the propeller unit,

e. an engine mounted in said boat,

. a gear on the drive shaft, and

. gearing loosely supported on said idler shaft operatively connecting the engine with said gear on the vrtical drive shaft.

11. The mechanism defined by claim 10, which includes a steering wheel rotatably mounted in the boat,

a flexible shaft connected to the wheel and extending into the main housing, a steering gear mounted in the lower housing, and gearing connected to the flexible shaft and operatively connected to the steering gear for rotating the lower housing, said gearing conncted to the flexible shaft and said steering gear comprising a shaft and pinion located in the idler shaft.

12. Drive mechanism for a boat comprising a. a stationary housing for outboard mounting on the stern of a boat,

b. a centrally located housing rotatable about a horizontal axis relatively to the stationary housing,

c. an idler shaft extending through said rotatable housing axially transversely of the boat and mounted at opposite ends in said stationary housing, said idler shaft having an opening extending therethrough axially perpendicular to the axis of the shaft,

d. a vertical drive shaft extending through said opening in the idler shaft,

e. an engine,

f. gearing operatively connecting said engine to the vertical drive shaft, and

g. a propeller unit rotatably mounted on the lower end of the rotatable housing and driven by said vertical shaft.

13. Drive mechanism defined by claim 12, in which the gearing operatively connecting said engine to the vertical drive shaft includes a train of gears loosely mounted on said idler shaft, an engine driven shaft provided with a fixed gear meshing with a gear of said train of gears, and a power accumulating gear on the vertical drive shaft.

14. Drive mechanism defined by claim 13 which includes a clutch gear splined on the vertical drive shaft movable into and out of engagement with the power accumulating gear.

15. Drive mechanism defined by claim 12, in which the idler shaft is provided with an extrusion surrounding said opening in the shaft, and said vertical drive shaft is supported by said extrusion.

16. Drive mechanism defined by claim 13, in which the idler shaft is provided with an extrusion surrounding said opening in the shaft, and said vertical drive shaft and power accumulating gear are supported by said extrusion.

17. Drive mechanism defined by claim 12, which includes steering means comprising a rotated shaft and pinion located in the idler shaft, a transfer gear in mesh with the pinion and a steering gear operatively connected to the lower housing to rotate the lower housing for directional control of the boat.

18. In combination with a boat, drive mechanism comprising a. a main housing consisting of stationary end members and a centrally located member rotatable relatively to the stationary members mounted outboard on the transom of the boat,

b. an idler shaft extending transversely of the boat having its ends mounted in said stationary members of the housing and having an opening extending through the center of the shaft in said rotatable member of the housing,

c. a vertical drive shaft extending through the opening in the idler shaft,

d. a single lower housing and a propeller unit in the lower housing located in alignment with the keel of the boat, said lower housing being rotatably mounted on the rotatable member of the main housing, and'said vertical drive shaft being operatively connected to the propeller unit,

e. a pair of engines mounted in said boat,

f. a shaft driven by each engine extending through the boat transom longitudinally of the boat, and p g. trains of gears loosely mounted on the idler shaft at opposite sides of the vertical drive shaft, each train of gears being operatively connected to one of the engine shafts and to said vertical drive shaft. 19. The drive mechanism defined by claim 18 which includes steering means inboard of the boat, and a steering means controlled shaft and pinion located in the idler shaft and operatively connected to the propeller unit.

20. Inboard-outboard drive mechanism for a boat which has a keel and a transom, said drive mechanism comprising a. a main housing mounted outboard on the transom of the boat, said housing having stationary end members and a centrally located member rotatable about a horizontal axis relatively to said stationary end members,

b. a hollow idler shaft extending transversely of the boat through said centrally located housing membet, with the idler shaft ends mounted in said stationary housing members, said idler shaft having an opening extending transversely through its center,

c. an extrusion in the form of a collar extending from the idler shaft around the opening of the shaft,

d. a vertical drive shaft extending through the opening in the idler shaft and through the extrusion,

e. a lower housing and a propeller unit in said lower housing located in alignment with the keel of the boat, said lower housing being rotatably mounted in the rotatable housing member to rotate about the axis of the vertical drive shaft, said vertical shaft being operatively connected to the propeller unit,

f. a power accumulating gear splined on the upper end of the vertical drive shaft,

g. a dog clutch splined on the vertical drive shaft and means for moving said dog clutch into driving engagement with the power accumulating gear for driving the vertical shaft and propeller unit,

. an engine mounted in the boat having a horizontal drive shaft extending through the boat transom,

'. a train of gears and clutch assembly loosely mounted on the idler shaft operatively connecting said engine shaft and power accumulating gear, and

'. steering wheel controlled power actuated gearing supported by the idler shaft and operatively connected with said lower housing, said power actuated gearing including a shaft and pinion located in the hollow idler shaft, a transfer gear, and a steering gear in mesh with the transfer gear. 

1. Drive mechanism for a boat comprising a. a housing for outboard mounting on the stern of a boat, b. an idler shaft having an opening extending therethrough, said shaft extending axially transversely of the boat and mounted at its ends in said housing, c. a vertical rotatable drive shaft extending through said opening in the idler shaft, d. a clutch gear on the upper end of the vertical drive shaft, said drive shaft and gear being supported by the idler shaft, e. an engine, f. gearing including a train of gears loosely mounted on said idler shaft operatively connecting said engine with said clutch gear on said drive shaft for rotating said shaft, and g. a propeller unit driven by said vertical shaft.
 2. Drive mechanism defined by claim 1, in which the gearing includes a power accumulating gear rotatable about the vertical shaft by power transmitted through said engine operated gears, and means actuating the clutch gear into and out of engagement with said power accumulating gear.
 3. Drive mechanism defined by claim 2, in which the means actuating the clutch gear comprises a pivotally mounted shifting fork engaging the clutch gear, an operating lever, and means pivotally connecting the lever and shifting fork for transmitting lifting and lowering movement to the fork and clutch gear.
 4. Drive mechanism defined by claim 3, in which the means actuating the clutch gear includes a rotatable clutch plate, clutch actuating rollers in tapered slots, and a clutch contacting plate forced by the rollers into contact with the shifting fork.
 5. Drive mechanism defined by claim 2, in which the gears loosely mounted on the idler shaft connecting the engine with the clutch gear comprise a pinion rotated by said engine, a power transfer gear driven by said pinion, a one way rolling clutch assembly engaged by said transfer gear, and a second transfer gear rotated by said clutch assembly for rotating said power accumulating gear.
 6. Drive mechanism defined by claim 5, in which the one way rolling clutch assembly comprises rollers movable to motion transmitting positions between the first and second transfer gears when the engine is operating and automatically movable to non-transmitting positions when the engine is idle.
 7. Drive mechanism defined by claim 1, in which the propeller unit includes a lower housing rotatable about the axis of the vertical shaft, and which includes a steering wheel controlled, power actuated gearing supported by the idler shaft and operatively connected with said lower housing to impart steering rotation to said lower housing and propeller unit.
 8. Drive mechanism defined by claim 7, in which the idler shaft is hollow, and the power actuated gearing includes a shaft and pinion in the hollow idler shaft, a transfer gear, and a steering gear in mesh with the transfer gear, said steering gear being held on the lower housing by a splined collar.
 9. Drive mechanism defined by claim 1, in which the idler shaft is provided with an extrusion perpendicular to the axis of the shaft surrounding said opening in the shaft, and in which the drive shaft and clutch gear thereon are supported by the extrusion of the idler shaft.
 10. In combinatioN with a boat, drive mechanism comprising a. a main housing mounted outboard on the stern of a boat, b. an idler shaft having an opening extending therethrough midway between the shaft ends, said shaft extending axially transversely of the boat and mounted at its ends in opposite ends of the housing, c. a vertical drive shaft extending through the opening in the idler shaft, d. a single lower housing and a propeller unit in the lower housing located in alignment with the keel of the boat, said lower housing being rotatably mounted on the main housing, and said vertical drive shaft extending into the lower housing and operatively connected to the propeller unit, e. an engine mounted in said boat, f. a gear on the drive shaft, and g. gearing loosely supported on said idler shaft operatively connecting the engine with said gear on the vrtical drive shaft.
 11. The mechanism defined by claim 10, which includes a steering wheel rotatably mounted in the boat, a flexible shaft connected to the wheel and extending into the main housing, a steering gear mounted in the lower housing, and gearing connected to the flexible shaft and operatively connected to the steering gear for rotating the lower housing, said gearing conncted to the flexible shaft and said steering gear comprising a shaft and pinion located in the idler shaft.
 12. Drive mechanism for a boat comprising a. a stationary housing for outboard mounting on the stern of a boat, b. a centrally located housing rotatable about a horizontal axis relatively to the stationary housing, c. an idler shaft extending through said rotatable housing axially transversely of the boat and mounted at opposite ends in said stationary housing, said idler shaft having an opening extending therethrough axially perpendicular to the axis of the shaft, d. a vertical drive shaft extending through said opening in the idler shaft, e. an engine, f. gearing operatively connecting said engine to the vertical drive shaft, and g. a propeller unit rotatably mounted on the lower end of the rotatable housing and driven by said vertical shaft.
 13. Drive mechanism defined by claim 12, in which the gearing operatively connecting said engine to the vertical drive shaft includes a train of gears loosely mounted on said idler shaft, an engine driven shaft provided with a fixed gear meshing with a gear of said train of gears, and a power accumulating gear on the vertical drive shaft.
 14. Drive mechanism defined by claim 13 which includes a clutch gear splined on the vertical drive shaft movable into and out of engagement with the power accumulating gear.
 15. Drive mechanism defined by claim 12, in which the idler shaft is provided with an extrusion surrounding said opening in the shaft, and said vertical drive shaft is supported by said extrusion.
 16. Drive mechanism defined by claim 13, in which the idler shaft is provided with an extrusion surrounding said opening in the shaft, and said vertical drive shaft and power accumulating gear are supported by said extrusion.
 17. Drive mechanism defined by claim 12, which includes steering means comprising a rotated shaft and pinion located in the idler shaft, a transfer gear in mesh with the pinion and a steering gear operatively connected to the lower housing to rotate the lower housing for directional control of the boat.
 18. In combination with a boat, drive mechanism comprising a. a main housing consisting of stationary end members and a centrally located member rotatable relatively to the stationary members mounted outboard on the transom of the boat, b. an idler shaft extending transversely of the boat having its ends mounted in said stationary members of the housing and having an opening extending through the center of the shaft in said rotatable member of the housing, c. a vertical drive shaft extending through the opening in the idler shaft, d. a single lower housing and a propeller unit in the lOwer housing located in alignment with the keel of the boat, said lower housing being rotatably mounted on the rotatable member of the main housing, and said vertical drive shaft being operatively connected to the propeller unit, e. a pair of engines mounted in said boat, f. a shaft driven by each engine extending through the boat transom longitudinally of the boat, and g. trains of gears loosely mounted on the idler shaft at opposite sides of the vertical drive shaft, each train of gears being operatively connected to one of the engine shafts and to said vertical drive shaft.
 19. The drive mechanism defined by claim 18 which includes steering means inboard of the boat, and a steering means controlled shaft and pinion located in the idler shaft and operatively connected to the propeller unit.
 20. Inboard-outboard drive mechanism for a boat which has a keel and a transom, said drive mechanism comprising a. a main housing mounted outboard on the transom of the boat, said housing having stationary end members and a centrally located member rotatable about a horizontal axis relatively to said stationary end members, b. a hollow idler shaft extending transversely of the boat through said centrally located housing member, with the idler shaft ends mounted in said stationary housing members, said idler shaft having an opening extending transversely through its center, c. an extrusion in the form of a collar extending from the idler shaft around the opening of the shaft, d. a vertical drive shaft extending through the opening in the idler shaft and through the extrusion, e. a lower housing and a propeller unit in said lower housing located in alignment with the keel of the boat, said lower housing being rotatably mounted in the rotatable housing member to rotate about the axis of the vertical drive shaft, said vertical shaft being operatively connected to the propeller unit, f. a power accumulating gear splined on the upper end of the vertical drive shaft, g. a dog clutch splined on the vertical drive shaft and means for moving said dog clutch into driving engagement with the power accumulating gear for driving the vertical shaft and propeller unit, h. an engine mounted in the boat having a horizontal drive shaft extending through the boat transom, i. a train of gears and clutch assembly loosely mounted on the idler shaft operatively connecting said engine shaft and power accumulating gear, and j. steering wheel controlled power actuated gearing supported by the idler shaft and operatively connected with said lower housing, said power actuated gearing including a shaft and pinion located in the hollow idler shaft, a transfer gear, and a steering gear in mesh with the transfer gear. 